WASHINGTON A U.S. Senate panel will meet next Thursday to discuss results of a much anticipated government study that looked at whether the biggest banks can borrow at lower interest rates because investors think they would be bailed out in a crisis.

Senator Sherrod Brown of Ohio, a Democrat, and Senator David Vitter of Louisiana, a Republican, who serve on the Senate Banking Committee, asked the Government Accountability Office more than a year ago to determine whether banks that are deemed "too big to fail" are able to borrow more cheaply than smaller banks can. Bank critics say that cheaper borrowing represents a market subsidy for the biggest institutions.

Brown leads the Subcommittee on Financial Institutions and Consumer Protection, which will take up the GAO report in a hearing on July 31. The report has not been made public yet.

U.S. Treasury Secretary Jack Lew and other officials have said publicly that any benefit for big banks such as JPMorgan Chase & Co and Citigroup Inc has shrunk since the 2007-2009 financial crisis. During the crisis, many financial services companies, including insurer American International Group Inc., were bailed out.

Regulators have worked to implement the Dodd-Frank Wall Street Reform and Consumer Protection Act of 2010, which sought to end bailouts by limiting banks' reliance on debt and forcing banks to plan for future crises.

The GAO report is expected to find a reduced subsidy for size. However, people familiar with the report said it would show that investors would feel safer with the biggest banks in a future economic meltdown because they still see a federal government bailout as possible. That could be part of why some borrowing subsidy persists.

In March, the International Monetary Fund said subsidies for U.S. banks' borrowing had fallen as of 2013 but that they might never disappear completely. On average, banks deemed systemically important still enjoy implicit subsidies of around 60 basis points compared with their less weighty peers, the IMF said.

Big banks and their lobbyists, on the other hand, say that U.S. lawmakers are not eager to bail out financial institutions. The lobbyists and their banking clients also point out that the large players in other industries can borrow more cheaply than their smaller competitors, even though those big companies do not expect to be bailed out in a crisis.